Copying lathe



Aug. 20, 1929. TQPHAM 1,724,981

COPYING LATHE Filed June 9, 1928 4 Sheets-Sheet 2 {Eilllllllllmllllllilll fifi lllllll lllllllllllllllllllll! i illlllul flml-mll' ll u L. E. TOPHAM COPYING LATHE Aug. 20, 1929.

Filed June 1928 4 Sheets-Sheet 3 Q i NQ 4 Aug. 20,-1929. E'TCPHAM 1,724,981

COPYING LATHE Fi led June 9, '1923 4,Sheets-Sheet 4 Fig.9. 7

Patented Aug. 20, 1929.

UNITED STATES tinsel Parent creme,

LAURENCE E. TOPHAM, OF WENT-TAM, MASSACHUSETTS, ASSIGNOB TC UNITED SHOE MACHINERY CUBESRATION, 0F EATER-SON, NEEV JERSEY, A CORPORATION OF NEW JERSEY.

Application filed June 9,

This invention relates to copying lathes and in its machine aspect is illustrated as embodied in a last lathe of the type disclosed in my application, Serial No. 530,214, filed January 18, 1922, of which this application is a continuation in part.

In the ordinary last lathe both right and left lasts are turned from a single model, the model and block being rotated in the same direction or in opposite directions, according to which species of last is being turned. This is called direct and reverse cutting, in the two cases, respectively. The small cutter head problem, the width grading problem generally, and the reversal of rotation in particular give rise to a number of inaccuracies in lateral reproduction. It is an object of the present invention to provide a practical machine which will overcome all these difiiculties which will be fully explained below, combining all the advantages of prior inventions which have dealt with special aspects of the complete problem such as, for example, the invention set forth in my application above mentioned, which shows a machine for direct cutting only.

A rsum of the conditions necessary for accurate lateral reproduction in the copying lathe will be of service here. The discussion will be based upon a last lathe of the ordinary type in which the model and block rotate about collinear axes in a swing frame and in which the centers of the cutter and model wheel lie on a line parallel to the axis of rotation of the swing frame. Such a machine is shown in the drawings. The application of the principles developed to any other type of machine will be clear.

It will also he assumed for the present that the cutter is on an axis parallel to that of the work, and the conditions of what has been called direct reproduction, that is, where the model and work piece are revolved in the same direction relatively to the model wheel and cutter centers, will be first considered. In the ordinary machine, and in the herein disclosed machine, this procedure will produce a right last from a right model; in the machine disclosed in the application referred to it produces a left last from a right model because of the reversal in direction of the longitudinal axis of the model in that machine.

f no width grading is being done, it is only necessary that the model wheel and cut- COPYING LATHE.

1928. Serial No. 284,078,

ter'be of the same effective dimensions and have their centers equally distant from those of the model and work respectively and that their centers lie in one plane passing through the above mentioned collinear model and block axes. This will effect absolute 1:1 correspondence in the corresponding lateral cross-section of the model and the work.

In case width grading is being done it is necessary that the model wheel center remain in the plane, hereinafter called the grading plane, determined by the modelwork axis and the cutter center, in order to maintain the similarity of conditions on the model and work sides of themachine. This is really the same conditionas mentioned in the preceding paragraph, the former instance being a special case. It has been the custom heretofore to accomplish width grading by moving the model wheel back and forth on a rectilinear slide. In case a slide frame, as distinguished from a swing frame, is used, the model wheel slide is made to work parallel to the direction of movement of the slide frame and there is no diihculty. If, however, it is desired 'to retain the peculiar advantages inherent in the swing frame, a purely rectilinear movement of the model wheel will not follow the grading plane, which swings about the cutter center as the model-work axis swings about the axis of rotation of the swing frame. When width grading in this way with a swing frame the point of cut rotates away from the cutter before or after the corresponding model point has fallen on the model wheel, owing to the variable displacement of the model wheel center from the grading plane due to the rotation of the swing frame itself. In-

the well-known Gilman lathe a swing frame of about 40 inch radius was used to flatten the curve in V which the model-work axis moved, but the width grading movement of the model wheel was still in a straight line having no close correspondence even with this flattened curve. In the disclosed machine the swing frame is only 7 inches in radius, whereby great rigidity is secured, and yet the model wheel is kept in the required plane by swinging it vertically around the fulcrum of a lever on which it is mounted, as explained in my application referred to.

The next question is that of reverse reproduction where the model and work are rotated in opposite directions. Here the conditions on the model and work sides of the machine must be just the reverse of each other, or in other words must be reflections of each other relatively to the grading plane. The requirement that the model wheel center remain in the grading plane determined by the model-work axis and the cutter centre remains unaltered. In addition, the model and work must have rotate d equal amounts in opposite directions from this plane at any given instant, in order to bring about the desired reverse relationship between the model and block. The mere driving of the model and work in opposite directions from a single shaft with equivalent gearing for each, which has been the previous practice, will not,in general, be enough to secure this re sult, if a swing frame is being used, since the rotation of the swing frame affects the reversely rotating model and block in opposite effective directions, increasing the absolute rotation of one and diminishing that of the other. The condition may also be stated as follows: Suppose similarly located lines to extend from the centers of the model and work to the center of the model wheel and cutter respectively, and suppose that these lines are frozen in, i. e. fixed to, the model and work; these lines lie in the grading plane heretofore discussed. It is necessary as the swing frame is moved in any way, the drive being stopped, that these frozen lines remain in this plane, or rotate equally away from it in opposite directions, in order to preserve the symmetry required for reverse cutting, irrespective of swing frame rotation. The machine of the present invention accomplishes the desired objectof keeping the frozen lines in the grading plane by means of suitable gearing in the model and work driving mechanism. The model and work can therefore be operated by identically sized gearings driven by two oppositely and equally rotating gears on the main frame. Another way of effecting the proper behavior of these frozen lines is shown in my copending application, Serial No. 253.068, filed February 9, 1928.

This feature of the invention is of particular importance in connection with the problem of anomalous width grading, discussed in my applications, Serial No. 429,719, filed December 10, 192-0, and Serial No. 530,214, filed January 18, 1922. In these applications I have shown mechanism for altering the width grading factor cyclically in correspondence with the cycle of rotation of the model and block, so that, for example, the bottom face of the last may be held unchanged while the additional material necessary in width grading is all put into the portion'above the bottom. This is accomplished by putting the width grading mechanism in neutral position during a predetermined portion of each rotation of the model and work, and in order that this portion may remain the same throughout the length of the model and work it is necessary that the rotation of the swing frame, due to changes in diameter of the model from point to point in its length, shall not affect the peripheral location of the contact points of the model and work with the model wheel and cutter, respectively. The gearing above mentioned solves this problem.

The condition that the cutter axis is to be at an acute angle with the model-work axis, as is the case in the Gilman small cutter head lathe, will now be introduced. (The advantages of this feature are explained in United States Letters Patent No. 1,137,117 and No. 1,330,535, issued on the applications of Frank S. Buck.) This introduces other necessary conditions to be satisfied without affecting any of those heretofore discussed. It is now necessary that the model wheel and cutter axes when considered in relation to the model and work respectively have the proper relation to the grading plane. In the case of direct cutting the orientations of the model wheel and cutter axes must be kept unchanged, since they must retain the same direct relation to the grading plane, which is done in the machine described herein and in that of the application referred to by a parallel mechanism which compensates for the rotation of the model wheel axis due to the ab0vementioned swing necessary to keep the model wheel center in the grading plane. In the case of reverse cutting, it is necessary that the two axes be oppositely and equally inclined to the grading plane and on opposite sides thereof at all times. This means that when the modelwork axis is on the face of the cutter, the model wheel axis, if the cutter axis is not in the grading plane (which it is not, in the machine shown) must be thrown equally to the opposite side of that plane from the cut-.

ter axis. The present invention provides a mechanism for moving the model wheel axis so that the grading plane bisects the angle between the model wheel and cutter axes when the model-work axis is on the face of the cutter, or in the so-called zero position. In order to maintain this relation of bisection as the swing frame and the grading plane move mechanism is provided by the present invent-ion for rotating the model wheel axis from this initial position about an axis parallel to the axis of rotation of the swing frame in the same direction as the grading plane rotation due to swing frame movement from the first described position, and twice as much in amount at any instant, measuring from the condition of things when the model-work axis is on the face of the cutter. This causes the model wheel axis to keep as far ahead of the grading r The pinion 4O drives the gear 42 on the plane on one side of it as the plane rotates, as the cutter axis falls behind it on the other side, or vice versa, so that the proper refiectional relation is established. In case width grading is being done, the rotation of the model wheel axis due to tipping it into the grading plane is compensated for as before.

These and other features of the invention comprising certain combinations and arrangements of parts will be apparent from the following description of a preferred embodiment of the invention shown in; the drawings, in which Fig. 1 is a plan View of the machine;

Fig. 2 is a front elevation;

Fig. 3 is a side elevation of the model wheel slide;

Fig. 4 is a transverse section of the machine taken on a plane designated by the line 44 in F 1.

Fig. 5 is a detail of the tipping mechanism from the model wheel axis;

Fig. 6 is a plan of the model wheel carriage mechanism;

Figs. 7, 9 and 10 are details of the gearing;

Fig. 8 is a diagram of the gearing, and

Fig. 11 is a detail of a portion ,of the mechanism shown in Fig. 4 illustrating the cyclic width grading cam.

The model and work drive in the swing frame will first be described.

The swing frame 10 has a square axis shaft 12 at a distance of 7 inches from which, in the machine shown, the model spindle 14 and work spindle 16 are mounted. The construction of this frame is more fully described in my application. Serial .No.,'

530,214, referred to. The model and work are rotated from a main shaft 18: which has a long pinion 20 on it meshing with a gear 21 mount-ed in the sliding model wheel carriage 22. The shaft 18, by means of a gear 23, drives a gear 24 mounted in the frame of the machine which drives a gear 26 of what we may callmore than double thickness (Fig. 10). The gear'26 engages a gear 28 of double thickness rotatably mounted on the cylindrical end of the shaft 12, but runs just free of the gear 30 which is likewise rotatable on the end of the shaft 12 and is spaced from the gear 28 by less than a single gear thickness. The gear 26 also engages the gear 32 which meshes with the gear 30. The gears 28, 30 are thus continuously driven in opposite directions, on the shaft 12.

The gear 28 meshes with a gear '34 on a rotatable shaft 36, mounted in the swing frame, and the gear 30 meshes with a similar gear 38 having a pinion 40 integral with it. rotating and slidable on the shaft 36.

model spindle 14. The shaft has on its right end (Fig. 2) a splined pinion 44 equal indiameter to the pinion 40, which drives a gear 46, equal to the gear 42, on the work gears 38, 40, a filler piece 47 is provided (Figs. 2 and 9) having one tooth 49 in the middle of a concave are as shown in Fig.

9, and located between the gears 38 and 40.

When these are slipped to the left in Fig. 2 the single-tooth 49 meshes with the gear 30 until the gear 38 has come into mesh with the gear 28, and then leaves the gear 30.

Thus no failure of proper engagement is pos-.

sible.

The gears 28, 30, 34, 382.11 have the same number of teeth, and the gears 40,44 have half as many teeth as the gears 42, 46. The distance on'centers of the shafts 12, 14 is equal to the distance of the shaft 12 to the model wheel cent-er 52 (Fig. 4) in the zero position, that is when the center of the model spindle 14 lies on the face-of the model wheel 54 in its own zero or nongrading position, the center of the model wheel being then in alinement with the center. of the cutter 56. This structure insures that the model and work shall, in reverse cutting, always turn equally in opposite directions from the grading plane (see Fig. 8), which will be seen as follows,

- If the gear 30 is fixed and the swing frame rotated, it can be shown that a radial line 58 (Fig. 8) of the gear 42 which passes through the line 52 joining the center of the model wheel in its zero position, and the cutter center, will always pass through this line irrespective of the position of the swing frame. Suppose the parts originally in the full line position (Fig. 8) with the angle 1,11 between the swing frame 10 and the line 12 52 and with the radius 58 passing through the point 52. Since the triangle 1252-14 is isosceles the angle at 14 is 9O t. Let the frame 10 swing out counterclockwise through an angle (1). The gears 38*40 will be rotated counter-clockwise through an angle twith regard to the swing frame 10, since the gears 30, .38 are equal, and the gear 42 will be turned clockwise through an angle of because of the relation between the diameters of the gears 40 and 42. The angle at 14 between the same radius 58 of the gear 42 (or model) and the swing frame will therefore be 9O, 1,[/ 115 which is the that the result attained is also true in direct cutting.

Another wayof stating the above result is that the model rotates one-half as fast as the swing frame and in the opposite direction, due to swing frame rotation, solely.

The mechanism for keeping the model wheel center in the grading plane when width grading is similar to that described in my application Serial No. 530,214, filed J anuary 18, 1922, above referred to, and in so far as it is the same, will be only briefly described here. The fanboard 59 is pivoted at 60 and operates a feeler bar 62 having a friction roller 64 in contact with the fanboard and pivoted to the model wheel slide 66 at 68. The model Wheel slide 66 is mounted in a standard 70 on the model wheel carriage 22. The fanboard 59 is linked to the swing frame 10 by a link 72, pivoted to them at 74 and 76 respectively. A rock shaft 78, mounted in the standard 70, has pinned on it a bell crank 80, 82 (Fig. 5). The arm is linked to the fanboard 59 by alink 84, 85, 86 engaging a rod 87 mounted on the fanboard, and along which the link 84, 85, 86 is carried by the model wheel carriage 22. The rock shaft 78 extends through a large hole in the model wheel slide 66 and carries a slideway 88 (Fig. 3) in which runs aslide 90, to which is pivoted at 92 one end 94 of a lever. The middle part of this lever is formed as a rock shaft 96 mounted in the slide 66 parallel to the spindles 14, 16. The front end 98 of the lever which is half as long as the arm 94 carries a little rock shaft 100 (Fig. 6) on the end of which, at an angle of about 30 is mounted the model wheel spindle 102, with its center 52 on the axis of the rock shaft. The little rock shaft 100 has a crank arm 104 (Fig. 4). The shaft 96 'hasrotatably mounted on it a bell crank 106, 108 one arm of which is linked to the arm 104 by a link 110, 112, 114. The figure 96, 100, 110, 114is a parallelogram. The other arm 108 of the bell crank is pivoted to a block 116 which runs in a slideway 118 in a slide 120 working vertically in the standard 70. The slideway 118 also contains a second block 122 pivoted to the end 124 of a lever rotatably mounted on the shaft 78. The other end 126 of this lever carries a latch 128 which 'canengage a notch 130 in the model standard 70 or a notch 132 in the bell crank arm 82, and is shown in engagement therewith in Fig. 4. The latch is held in either position by a spring 134. When the latch is in the notch 130, the lever 124, 126 is turned clockwise from the Fig. 4 position, the slide 120 is raised and the bell crank 106, 108 and link 104 turned counter-clockwise, with the little rock-shaft 100, bringing the model wheel I spindle 102 into parallelism with the cutter spindle 136, when the parts are in the zero position. In width grading, the movement of the slide 66 carries the slide along the slide 88 which is continuously tipped in accordance with the fanboard movement, thus tilting the lever 94 about the pivot 96 and giving a vertical movement to the model wheel. In my application Serial No. 530,- 214, above-mentioned, it is "shown that this structure will keep the model wheel center in the grading plane and that the parallelogram 96, 100, 110, 114 will preserve the orientation of the model wheel spindle 102, keeping it in the same angular relation to the grading plane as the cutter axis. In this adjustment, which is that for direct cutting, the bell crank 106, 108 does not rotate. The dotted position of the model wheel 54 in Fig. 4 refers to the situation ust described. The projection of the position of the model wheel spindle on the plane of Fig. 4 is indicated at 102 and the grading plane at 138. It is clear that the spindle 102 will remain in the same orientation in space as the grading plane moves. This orientation is the same as that of the cutter spindle or axis, as it should be in direct cutting.

In reverse cutting it is necessary to shift the model wheel spindle 102 to its reflection indicated at 102 (Fig. 4) relatively to the grading plane, when the machine is in the zero position, and move it so that the grading plane 138 will always bisect the angle 102-l02 as the swing frame and grading plane swing (Fig. 4). The mechanism already described is so designed that shifting the latch 128 to the notch 132 will swing the model wheel spindle through just the proper angle, the model wheel 54 taking the full line position in Fig. 4. The lever 124126 is now fast to the bell crank 80, 82..

The distance 60-74 is twice the distance 1276 so that the fanboard will swing half as fast as the swing frame. The distance 6086 is twice as great as the distance 7884 so that the bell crank 80, 82 will swing twice as fast as the fanboard or just as fast as the swing frame. The bell crank 106, 108 will swing at the same rate. It has been shown in my application above mentioned that the rate of rotation of the grading plane 138, with the described construction, is one-half the rate of swing frame rotation, and it is obvious that the axis 102' turns in the same direction as the grading plane as the swing frame rotates. bus the line 102 will turn with, and twice as fast as, the line 138, thus preserving the reflectional relation between the model wheel spindle 102 and the cutter spindle 136 relatively to the grading plane.

The width grading factor is adjusted by a handle 1&0 having a worm 1 12 on its shaft, which turns a segment 144 attached to a crank arm 146, linked to a slide block 148 in a segmental slide 150 pivoted at 152 on the model wheel carriage. The block 1&8 is also linked to the feeler link 62 by a link 153. A full explanation of this mechanism will be found in my applications already mentioned.

Briefly it may be stated that when regular width grading is being done the segment 150 will be held motionless as by connecting its arm 15a with the central shaft of the gear 21 by a link 156 as shown. l hen irregular width grading is to be done, as explained in the applications referred to, a cam 158 will be mounted on the central shaft of the gear 21, and fixed to the gear 21 in any lesired manner, as shownin Fig. 11, cooperating with a cam roll 160 on the end of the arm 15st held against the cam by a spring 162. The gear 21 is arranged to rotate in the same period as the model, and the cam 158 will thus impart a corresponding cycle of movement to the segment 150 about its center 152. In case the block 1 18 is adjusted anywhere in the segment 150 except over its center of swing 152, this will cause a cyclic movement of the feeler arm 62, with a correspondin cycle of values of' the width grading factor.

It has been explained above that, in irregular width grading, it is necessary to preserve the proper relation, identical when in direct cutting, and reflectional when in reverse cutting, between the model and block respectively and the grading plane.

This is effected, in the illustrated emboeiment of the present invention, by the construction of gearing shown in and already discussed in connection with Fig. 8.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a machine of the class described, a main frame, a model wheel, a swing frame equipped for effecting rotation of a model, and a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame in one direction, to rotate the model in the swing frame in the opposite direction at one-half the angular velocity of the swing frame, whereby a certain radial plane of the model will always point to the zero position of the model wheel center, as far as the swing frame rotation is concerned.

2. In a machine of the class described, a swing frame equipped for effecting rotation of a model and a block, and means for effecting the rotation constructed and arranged to impart to the model and block, on rotation of the swing frame, an angular velocity in the swing frame opposite in direction to that of the swing frame and of one-half its magnitude.

3. In a machine of the class described, a main frame equipped for effecting rotation of a model, and a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame, to rotate the model in space at one-half the angular velocity of the swing frame, whereby a certain radius of the model will always be directed toward a certain point, as far as the swing frame rotation is concerned.

I. In a machine of the class described, main frame, a model wheel, a swing frame equipped for effecting rotation of a model, and a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame, to rotate the model in space at one-half the angular velocity of the swing frame, whereby a certain radial plane of the model will always pass through zero position of the model wheel center, as far as the swing frame rotation is concerned.

5. In a last lathe, a swing frame comprising a bar at the axis of rotation of the swing frame, a model supporting arm arranged to slide along the bar, the distance between the axes of swing and model being less than ten inches, and gearing for driving the model arranged to produce acom ponent angular velocity of the model in space, due to rotation of the swing fran e, equal to one-half the angular velocity of the swing frame.

6. In a machine of-the class described, a main frame, a swing frame equipped for effecting rotation of amodel, and a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame, to rotate the model in space suiiiciently to keep a certain radius of the model always directed toward a certain fixed point in space.

7. In a machine of the class described, a cutter, a main frame, a swing frame equipped for effecting rotation of a block, and a train of gearing extending from the block into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame in one direction, to rotate the block in the swing frame in the opposite direction at one-half the angular velocity of the swing frame, whereby certain radial plane of the block will always point to the cutter center, as far as the swing frame rotation is concerned.

8. In a machine of the class described, a swing frame having means for effecting rotation of a model and a block in opposite directions, and means for effecting said rotation constructed and arranged to impart to the model and block, on rotation of the swing frame, an angular velocity in the swing frame opposite in direction to that of the swing frame and of one-half of the magnitude of the angular velocity of the swing frame.

9. In a machine of the class described, a main frame, a swing frame having means for effecting rotation of a model and a block in opposite directions, and trains of gearing extending from the model and block respectively into the main frame of the machine, said trains being constructed and arranged, upon rotation of the swing frame, to rotate the model and block in space at onehalf the angular velocity of rotation of the swing frame, whereby certain radii of the model and block respectively will always be directed toward certain points, as far as the swing frame rotation is concerned.

it). In a machine of the class described, a main frame, a model wheel, a swing frame having means for effecting rotation of a model and a block in opposite directions and trains of gearing extending from the model and block respectively into the main frame of the machine, said gearing trains being constructed and arranged, upon rotation of the swing frame, to rotate the model and block in space at one-half the angular velocity of the swingframe, whereby certain radial planes of the model and block will always pass through the zero positions of the model wheel center and of the cutter center respectively, as far as the swing frame rotation is concerned.

11. In a last lathe, a swing frame com.- prising a bar atthe axis of swing, model and block supporting arms on the bar, the distance between the axes of swing and model beine' less than ten inches, and gearing for driving the model and block in opposite directions arranged to produce a component angular velocity of the model and block relatively to the swing frame, due to rotation of the swing frame, equal to onehalf the angular velocity of the swing frame.

12. In a machine of the class described, a main frame, a swing frame equipped for reflecting rotation of a block, and a train of gearing extending from the block into the main frame of the machine, said gearing being constructed and arranged, ugon rotation of the swing frar e, to rotate the block in space sufficiently to keep a certain radius of the bloc-z always directed toward a certain fixed point in space.

13. In a. copying lathe, a model wheel, a

. tively to the cutter, a swing frame, means for rotating a model and a block in the swing frame in opposite directions, the axes of the model wheel and cutter being oblique to those of the model and block, and means for preserving a symmetrical relation between the model wheel and cutter axes relatively to the plane passing through the axes of rotation of the model and block and the cutter center.

14. In a copying lathe, a swing frame, means for rotating a model and a block therein, a. model wheel and a. cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique model wheel axis, and means for continuously turning the rock shaft to keep the model wheel axis and the cutter axisin symmetrical relation to the plane passing through the axes of rotation of the model and block and the cutter center.

15. in a copying lathe, a swing frame, means for rotating a model and a block therein, a model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique model wheel axis, and means for continuously turning the rock shaft to keep the model wheel axis and the cutter axis equally inclined to planes through the model wheel center and model axis, and the cutter center and block axis respectively, but on opposite sides of said planes respectively.

16. In a copying lathe, a swing frame,

means for rotating a model and a block therein, a model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique model wheel axis, means for holding the rock shaft to keep the model wheel axis in the same orientation as the cutter axis relagrading plane on the same side thereof, and means for keeping the model wheel axis in the same orientation as the cutter shaft relatively to the grading plane, but on opposite sides thereof, at will.

17. In a copying lathe, a swing frame, means for rotating a model and a block therein, a model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique model wheel axis, a movable member for turning the rock shaft, a second member rotating with the swing frame, and means for locking the first-named member in a fixed position to preserve the orientation of the model wheel axis, or to the second-named member to cause the model wheel axis to rotate with the swing frame.

18. In a copying lathe, a swing frame, means for rotating a model and a block therein, a, model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique.

model wheel axis, a movable member for turning the rock shaft, a second. member rotating with the swing frame, and means for locking the first-named member in a fixed position to preserve the orientation of the model wheel axis, or to the second-named member to cause the model wheel axis to rotate withthe same angular velocity as the swing frame.

19; In a copying lathe, a swing frame, means for rotating a model and a block therein, a model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique model wheel axis, and means for rotating the rock shaft at substantially the angular velocity of the swing frame.

20. In a copying lathe, a swing frame, means for rotating a model and a block therein, a model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rock shaft parallel to the model axis and carrying the oblique model wheel axis, and means for rotating the rock shaft at substantially the angular velocity of the swing frame and in the same direction.

21. In a copying lathe, a swing frame, means for rotating a model and a block therein, a model wheel and a cutter rotating on axes oblique to the axes of rotation of the model and block, a rockshaft parallel to the model axis and carryin the oblique model wheel axis, and means connecting the rock shaft to the swing frame for effecting rotation of the rock shaft at substantially the same angular velocity as that of the swing frame.

2 In a copying lathe, a swing frame arranged for carrying and rotating a model and a block, a cutter having its axis oblique to the axis of rotation of the swing frame, a rock shaft arranged parallel to the axis of rotation of the swing frame, and having a model wheel axis extended angularly therefrom on which a model wheel is mounted, means for holding the rock shaft with the model wheel axis and the cutter axis in the same relation to the plane defined by the model and block axes and the cutter center, means for swinging the rock shaft to keep the model wheel axis and the cutter axis in symmetrical relation to the said plane, and means for shifting the model wheel center to keep it in the said plane as the swing frame turns.

23. In a copying lathe, a swing frame arranged to carry a model and a block, a cutter having its axis oblique to the'axis of rotation of the swing frame, a swinging lever,

a rock shaft mounted on the lever parallel to the axis of rotation of the swing frame, an extension mounted obliquely on the rock shaft and forming a model wheel axis, means for swinging the lever with its attached model wheel axis to keep the model wheel center in the plane defined by the model and block axes and the cutter center, and means for rotating the rock shaft to keep the model wheel and cutter axes in symmetrical relation to the grading plane including means for compensating for the rotation of the rock shaft in space due to the swinging of the said lever.

24. In a copying lathe, a swing frame arranged to carry a'model and a block, a cutter having its axis oblique to the axis of rotation of the swing frame, a swinging lever, a rock shaft mounted on the lever parallel to the axis of} rotation of theswing frame, an extension mounted obliquely on the rock shaft and forming a model wheel axis, means for swinging the lever with the rockshaft to keep the model wheel center in the grading plane, means for rotating the rock shaft at substantially the angular velocity of the swing frame, and means for compensating for the rotation of the rock shaft due to the swinging of the said lever.

25. In a copying lathe, a swing frame arranged to carry a model and a block, acutter having its axis oblique to the axis of rotation of the swing frame, a swinging lever, a rock shaft mounted on the lever parallel to the axis of rotation of the swing frame, an extension mounted obliquely on the rock shaft and carrying a model wheel, means for swinging the lever to keep the model wheel centerin the grading plane, a connection bet-ween the rock shaft and the swing frame operating to rotate the rock shaft at substantially the angular velocity of the swing frame, and a parallel motion device for compensating for the rotation of the rock shaft due'to the swinging of the said lever.

26. In a copying lathe, a swing frame, a. model wheel carrying slide, a rock shaft mount-ed on said slide having an oblique extension carrying a model wheel, a slide working in said model wheel carrying slide, and two bell cranks connected with said second named slide, one of said cranks being connected with the rock' shaft and the other said crank being connected to the swing frame. r

27. In a copying lathe, a swing frame, a model wheel carrying slide, a rock shaft mounted on said slide having an oblique extension carrying a model wheel, a slide working in said model wheel carrying slide, and two bell cranks connected with said second-named slide, one of said cranks being connect-ed with the rock shaft and the other said crank being connectible at will to the swing frame or to the model wheel carrying slide.

28. In a copying lathe, a swing frame, a model wheel carrying slide, a rock shaft mounted on said slide having an oblique extension carrying a model wheel, a slide working in said model wheel carrying slide transversely to the direction of movement of the model wheel carrying slide, and two bell cranks connected with said second named, slide, one of said cranks being connected with the rock shaft and the other said crank being connected to the swing frame.

29. In a machine of the class described, a main frame, a model wheel, a swing frame equipped for effecting rotation of a model, a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame in one direction, to rotate the model in the swing frame in the opposite direction at one-half the angular velocity of the swing frame, whereby a. certain radial plane of the model will always point to the Zero position of the model wheel center, as far as the swing frame rotation is concerned, and a width grading mechanism for imparting width grading movements to the model wheel.

30. In a machineof the class described, a main frame, a model wheel, a swing frame equipped for effecting rotation of a model, a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame in one direction, to rotate the model in the swing frame in the opposite direction at one-half the angular velocity of the swing frame, whereby a certain radial plane of the model will always point to the zero position of the model wheel center, as far as the swing frame rotation is concerned, width grading mechanism for imparting width grading movements to the model wheel, and means for automatically varying the width grading factor during the production of a work piece. 7

31. In a machine of the class described, a main frame, a model wheel, a swing frame equipped for effecting rotation of a model, a train of gearing extending from the model into the main frame of the machine, said gearing being constructed and arranged, upon rotation of the swing frame in one direction, to rotate the model in the swing frame in the opposite direction at one-half the angular velocity of the swing frame, whereby a certain radial plane of the model will always point to the zero position of the model wheel center, as far as the swing frame rotation is concerned, width grading mechanism for imparting width grading movements to the model wheel, and means for cyclically varying the width grading factor during the production of a work piece.

32. In a machine of the class described, a main frame, a model wheel, a swing frame equipped for effecting rotation of a model, a train of gearing extending from the model into the main frame of the machine, said gearing bein constructed and arranged; upon rotation of the swing frame in one direction, to rot-ate the model in the swing frame in the opposite direction at one-half the angular velocity of the swing frame, whereby a certain radial plane of the model will always point to the zero position of the model wheel center, as far as the swing frame rotation is concerned, width grading mechanism for imparting width grading movements to the model wheel, and means for cyclically varying the width grading factor, in correspondence with the cycle of model rotation, during the production of a work piece.

33. In a machine of the class described, a swing frame having means for effecting rotation of a model and a block in opposite directions, means for effecting said rotation constructed and arranged to impart to the model and block, on rotation of the swing frame, an angular velocity in the swin frame opposite in direction to that of the swing frame and of one-half of the magnitude of the angular velocity of the swing frame, and a width grading mechanism for imparting width grading movements to the model wheel.

34. In a machine of the class described, a swing frame having means for effecting rotation of a model and a block in opposite directions, means for effecting said rotation constructed and arranged to impart to the model and block, on rotation of the swing frame, an angular velocity in the swing frame opposite in direction to that of the swing frame and of one-half of the magnitude of the angular velocity of the swing frame, width grading mechanism for imparting width grading movements to the model wheel, and means for automatically varying the width grading factor during the production of a work piece.

35. In a machine of the class described, a swing frame having means for effecting rotation of a model and a block in opposite directions, means for effecting said rotation constructed and arranged to impart to the model and block, on rotation of the swing frame, an angular velocity in the swing frame opposite in direction to that of the swing frame and of onehalf of the magnitude of the angular velocity of the swing frame, width grading mechanism for imparting width grading movements to the model wheel, and means for cyclically varying the width grading factor during the production of a work piece.

36. In a machine of the class described, a swing frame having means for effecting rotation of a model and a block in opposite directions, means for effecting said rotation 5 constructed and arranged to impart to the model and block, on rotation of the swing frame, an angular velocity in the swin frame opposite in direction to that of the swing frame and of one-half of the magni- 10 tude of the angular velocity of the swing frame, width grading mechanism for imparting width grading movements to the model wheel, and means for cyclically varying the width grading factor, in correspondence with the cycle of model rotation, during the production of a work piece.

In testimony whereof I have signed my name to this specification.

LAURENCE E. TOPHAM. 

